A 48-year-old woman presents with progressive memory loss, peripheral neuropathy, and ataxia. Vital signs are stable (BP 118/76, HR 72, RR 14, Temp 37°C). MRI demonstrates cerebellar atrophy. Laboratory studies reveal severely depressed total cholesterol at 85 mg/dL, undetectable LDL cholesterol, and normal triglycerides at 110 mg/dL. Genetic testing identifies a SREBP-2 mutation. She denies statin use. Which mechanism best explains her neurological manifestations?

1. A)Impaired synthesis of apolipoprotein E in astrocytes
2. B)Accumulation of cholesterol-depleted HDL particles in the brain
3. C)Defective cholesterol homeostasis leading to inadequate myelin synthesis in the nervous systemGABARITO
4. D)Oxidative stress from absent antioxidants in low-density lipoproteins
5. E)Enhanced lipoprotein lipase activity degrading cerebral lipoproteins